MESS = tissue injury points + limb ischaemia points (doubled if ischaemia time >6 hours) + shock points + age points. Total possible score 2-14.

Domain	Category	Examples	Points
Skeletal/soft-tissue injury	Low energy	Stab, simple fracture, low-velocity pistol gunshot	1
	Medium energy	Open or multiple fractures, dislocation, moderate crush	2
	High energy	High-speed motor vehicle crash, rifle gunshot, severe crush	3
	Very high energy	High-energy trauma with gross contamination or farm/industrial mechanisms	4
Limb ischaemia	Mild	Pulse reduced or absent but perfusion clinically normal	1
	Moderate	Pulseless limb with paraesthesia and diminished capillary refill	2
	Advanced	Cool, paralysed, insensate limb	3
Shock	Normotensive	Systolic BP ≥90 mmHg throughout resuscitation	0
	Transient hypotension	Systolic BP <90 mmHg but responsive to resuscitation	1
	Persistent hypotension	Ongoing systolic BP <90 mmHg in ED or operating theatre	2
Age	<30 years		0
	30-50 years		1
	>50 years		2

When warm limb ischaemia time exceeds 6 hours, double the limb ischaemia domain score before summing the MESS.

Mangled Extremity Severity Score (MESS)